Writing instrument



FIG. 1 is a front elevation view of a writing instrument in accordance with my new design;

FIG. 2 is a rear elevation view thereof;

FIG. 3 is a right-side elevation view thereof;

FIG. 4 is a left-side elevation view thereof; and,

FIG. 5 is a right front perspective view thereof.

The broken lines on the clip in FIG. 1 and FIG. 5 are included to show a feature that forms no part of the claimed design. 

CLAIM The ornamental design for a writing instrument, as shown and described. 